PROJECT SUMMARY (ABSTRACT). The HIV Care Continuum is a compelling epidemiologic framework describing the movement of people living with HIV/AIDS through care, including diagnosis, linkage and retention in care, use of antiretroviral therapy (ART), and ultimately, viral suppression. Health policies may profoundly influence outcomes along the Care Continuum, and these effects may be modified across regions and through individual contexts. In observational cohorts, retention in clinical care, ART use, and viral suppression proportions have varied depending on available data and the population under study. The US National HIV/AIDS Strategy (updated to 2020) and the revised 2013 World Health Organization ART guidelines also reference milestones in the Care Continuum. Because the Patient Protection and Affordable Care Act (ACA) and other national health policies in North and Latin American countries aim to improve healthcare access and reduce health disparities, describing the effect of policy and contextual factors on Care Continuum outcomes in these settings is of great interest to epidemiologists, clinicians, and policy makers. This research seeks to quantify health policy, sociodemographic, contextual, and geographic patterns and correlates of HIV Care Continuum outcomes among HIV-infected persons in the United States (US), Canada, and Mexico. Contextual factors include psychiatric illness, regional poverty, residential urbanicity, and other individual and environmental characteristics. The North American AIDS Cohort Collaboration on Research and Design (NA- ACCORD) and Caribbean, Central and South America network for HIV epidemiology (CCASAnet) provide rich data sources in which to conduct this work. Aim 1 will quantify disparities in Care Continuum outcomes in North and Latin America, assessing health system, demographic, risk, contextual, and geographic differences. Because research into the influence of contextual factors and health system characteristics on Care Continuum outcomes in longitudinal cohorts with clinical care data have been sparse or geographically limited, this analysis will be novel and of significant importance. Aims 2 and 3 will provide inferences about the ACA's effects on improving healthcare among HIV-infected individuals in care in the US. The state-led expansion of Medicaid coverage under the ACA will be used as a quasi-experiment to assess effects on Care Continuum and other HIV disease outcomes, comparing pre-ACA (pre-2014) to ACA implementation periods.